Stepladder



May 13, 1952 J. B. BELL 2,596,521

STEPLADDER v Filed May 7, 1949 2 SHEETS-Sl-EET 1 May 13, 1952 J. B. BELL2,596,521

STEPLADDER Filed May '7, 1949 2 SHEETS-SHEET 2 INVENTOR A oma P3642Patented May 13, 1952 UNITED STATES PATENT OFFICE STEPLADDER Jerome B.Bell, Wallingford, Pa.

Application May 7, 1949, Serial No. 92,035

4 Claims.

The present invention relates to step ladders.

A purpose of the invention is to permit a step ladder to fold into acomparatively flat form and occupy a minimum of space in foldedposition, while at the same time having ample depth of step when theladder is opened up, thus providing security and safety of tread on theladder.

A further purpose is to provide a step positioning bar pivotallyconnected to the individual lower steps and below the top step, andpreferably to make such bar extend parallel with the front rails.

A further purpose is to employ an interlocking system of upper and lowerlimiting bars interconnected by an intermediate limiting bar to limitthe opening of the rails in opening position.

A further purpose is to make the distance be tween the pivots of theupper and lower limiting bars on the front rail the same as the distancebetween the pivot of the lower limiting bars on the front rail and thepivot of the intermediate limiting bar on the lower limiting bars.

A further purpose is to make the length of the intermediate limiting barbetween its pivots the same as the distance between the pivot of theupper limiting bars on the front rail and the pivot connection betweenthe upper limiting bars and with the intermediate limiting bars.

A further purpose is to locate a stop on the lower limiting bars towardthe back rail with respect to the pivotal connections between the lowerlimiting bars and the intermediate limiting bar.

A further purpose is to locate a stop adjacent the pivot of the upperlimiting bars on the back rail.

Further purposes appear in the specification and in the claims.

Figure 1 is a perspective mainly from the front showing the ladder ofthe invention in open position.

Figure 2 is a perspective partly from the rear showing the open ladder,with a portion of the top step broken away to illustrate the steppositioning bar.

Figure 3 is a section of Figure 1 on the line Figure 4 is a fragmentaryend elevation of the folded ladder showing the limiting bars in foldedposition.

Figure 5 is a fragmentary section corresponding to Figure 3 but showingthe folded ladder.

Figure 6 is a fragmentary perspective of the rear rail showing thelimiting bars and the pivotal connection thereto.

Figure 7 is a transverse perspective through one of the rails showing avariation in the manner of pivoting the limiting bars.

Figure 8 is a fragmentary end elevation of the ladder of the invention,showing a variation in the pivot support for the rear rails, with thladder open.

Figure 9 is a view corresponding to Figure 8, with the ladder folded.

Describing in illustration but not in limitation and referring to thedrawings:

In the prior art step ladders, where it is desired to make the ladderfold into a very compact form, the tendency has been to use very narrowsteps which are uncomfortable and unsafe for the user. By the presentinvention comparatively wide or deep steps are used, while at the sametime the ladder is enabled to fold into a very compact form.

The single limiting bar construction employed in the prior art has insome cases failed to provide adequate limitation when open, resulting inaccidents due to unexpected collapse of the ladder when the user hasbeen subjected to some unexpected force incident to the work he has beendoing. By the present invention a double system of interconnectedlimiting bars is employed, which is much less likely to become dislodgedand is much less subject to the danger of breakage.

The ladder of the invention comprises front rails 20, rear rails 2|, atop step 22 and lower steps 23 and 24.

The rails are suitably made of any desirable material, such as wood, ormetal, but preferably comprise metallic channel or box sections asshown. The rails conveniently have cushion feet 25 at the bottom,suitably of rubber. The rails are desirably diverged outwardly at 26 toprovide wide spacing at the feet for greater stability.

The steps may desirably be formed of any suitable material, such as woodor metal. metal stampings being desirable. Any suitable antifriction orroughening surface may be used on the steps. The top step carriesbeneath it brackets 21 at each end, suitably attached to the step, whichpivotally interconnect with the front rails at 28 and with the backrails at 30.

The back rails are cross braced by bars 3| suitably cross connected atthe middle for greater strength.

Each of the lower steps 23 and 24 is pivotally connected at 32 at itsends with the front rails, pivot brackets 33 on the steps desirablymaking the connections. It will be evident that the shorter the brackets33 and the closer the pivots 32 to the top of each step, the flatterwill be the fold of the ladder and the more nearly flush will be thefolded position of the steps with respect to the frontrails. The step 24below the bend 26 in the rails has diagonal ends 54 to conform to therails in folding.

At the rear of each of the lower steps pivotal connection is made at 34,suitably through a pivot bracket 35 with astep positioning rail 36 whichextendsbehind'the steps and makes pivotal connection beneath the topsteps at 31 suitably on a pivot bracket 38 secured to the bottom of thetop step. The positioning bar 3'5 as shown in Figures 3 and preferablyremains at all times parallel with the front rails 20, so thatthe steps,the front rails and the step positioningrbarimake a parallelogram.

The improved limiting bar construction at the rails comprises lowerlimiting bars 40 and 4| pivotally interconnected .at 42. A slot 43suitably in1the upper-portion .of the bar M receives a stop 44 on theendof-bar lfl to limit the-motion of :the .lower limiting barsdfl and Mdownward. Thelower limiting bar Allis pivotally interconnected with thefront .rail .at 45 while the lower limiting bar 4| is pivotallyinterconnected with the back rail at 46. In open position the lowerlimiting bars can "desirably be approximately horizontaLlocated howeverabove the point 26 at which the rails diverge.

Above the-lowerlimiting .bars upper limiting bars A! and 48 .extendacross between the rails, being pivotally interconnected at '50 near themiddle. The upper limiting .bar 41 is pivotally connected to :thefrontrailat 28 and the upper limiting bar 48 is-pivotally connected tothe back rail at 51,:suitably by a stud stop extending out sufiicientlyto prevent the lower-limiting bars in folded position from.movingbeyondthe upper limiting bars as best seeninlFigure 6. To pre- 7 ventinterference the lower limiting bars are desirablyspaced out from therails as by washers 52 while the .upper .limiting bars are positionedcloser to the rails as shownin Figure 6. Thus a slight overlapping ofthe bars is possible in folded position.

The upper .andlower'limiting bars are interconnected by .an intermediatelimiting bar 52 pivoted at one end'to the lower limiting bars at 53 andpivoted at the other end to the upper limiting bars at 50, the pointwhere the upper limiting'bars pivot to one another. The pivot 53 ispreferably located on the side toward the front rail of the pivotalconnection "E2 between the lower limiting bars. In open position theintermediate "limitingbar '52 is inclined off the vertical as shown,tending to prevent the possibility that verticals components oftorsional forces normally encountered in the ladder could cause thelimiting bars .to break and thus .permit the :ladder to fold at a timewhich is notintended. v s

.It has been found very desirable to employ a certain relation oflengths,-creating a trapezoidal character 7011 the front and also on theback portion of the limiting bars. The distance between the pivotalconnection of the lower limiting bars with the front rail "and thepivotal connection 26 of the upper limiting bars with the front railshould equal the distance between the pivotal connection 45 of the lowerlimiting bars and the .front rail and the pivotal connection 53 betweenthe intermediate limiting bar and the lower limiting bars.

the'two lower limiting'barsextend in prolongation of one another andalmost horizontal, while the two upper limiting bars extend inprolongation-.of one another and sharply inclined toward the rear, theintermediate relating bar being in- -'clined-'si'milarly to the frontrails. The lock between theslot 43 and the stop 44 prevents the"limiting'bars'from travelling beyond this straight position.

While the embodiments shown illustrate limiting' lear-s-on both sides ofthe ladder, and illustrate-a lsingle step positioning bar, it will beevident that theinvention is not limited to use of any particular numberof sets of limiting bars, nor to the use-of a-single step positioningbar as distinguished from a plurality of step positioning bars-as:desired.

'The detail as to how the pivotal connection is to'be made to the steps,and whether-the pivots are carried-clearacross from one tothe'other ofthe steps'or are individual-on each side-is not to 'be regarded as vitalin the invention. It has been found thatadvantage can be obtained bypivoting the limiting bars-on the front and back rails insid the channelsections 'of the rails, as indicated by pivo 55 in Figure '7. Bycarrying the pivots -55 of Figure 7 clear across the channel andlocating washers 5! around the pivots, the functionof the stop 5| intheform of Figures 1 to Binclusiveis performedbythe vrashersEl.

Asshown inFigures 8 and 9, the top step can fold flatter if theipivotalconnection between the top step and the rear rails is carried fartherbelow thetops tep' err-brackets 21 than the pivotal connection betweenthe top step and the front rails on brackets 1 The additional length ofbracket 2 l'should correspond-to the depth of the front rail section.

In operation it will be understood that in closing the ladder from theopen position as shown, the user should grasp the lower limiting barsnear thecenter and cause the limiting bars to break upward at theirpivots %2, at the same time of course causing a similar deflection inthe upper limiting barsdue to the pressure transmitted upward throughthe intermediate limiting bars 52. At the same time the front and backrails are pivoted toward one another, cau's'ing'the ladder to fold. Thestep positioning bar'iit automatically swings the lower steps into the.positions shown in Figures 4 and 5, thus producing 'a very compactfolded ladder. When the ladder reaches its fully folded position, thepin 5| prevents thelimiting bars from moving too far.

To open the ladder it is merely necessary to pull the rails apartthestep positioning bar automatically positioning the lower steps in thecorrect position when the rails are fully open. To assure that thelimiting bars are fully locked, the user should press down on the middleof the limiting bars on both sides to insure that the stops M engageri ntheslots #3.

In view of my invention and disclosure variations and modifications tomeet individual whim or particular needwill doubtless become evident toothers skilled in the art, to obtain all or part of the benefits of myinvention without copying the structure shown, and I, therefore, claimall such insofar as they fall within the reasonable spirit and scope ofmy claims.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is:

1. In a step ladder, front and back rails, a top step pivotallyconnecting th front and back rails, lower limiting bars extendingbetween one front rail and the adjoining back rail, pivotally connectedto the respective rails and to one another, upper limiting barsextending across between the same front and back rails, pivotallyconnected to those front and back rails at points above the lowerlimiting bars and pivotally connected to one another and an intermediatelimiting bar extending across between the upper and lower limiting barsand pivotally connected to the upper and lower limiting bars.

2. In a step ladder, front and back rails, a top step pivotallyconnecting the front and back rails, lower limiting bars extendingbetween one front rail and the adjoining back rail, pivotally connectedto the respective rails and to one another, upper limiting barsextending across between the same front and back rails, pivotallyconnected to the front and back rails at points above the lower limitingbars and pivotally connected to one another and an intermediate limitingbar extending across between the upper and lower limiting bars,pivotally connected to the lower limiting bars, and pivotally connectedto the upper limiting bars where they pivotally connect to one another,the distance between the pivotal connection of the lower limiting barsto the front rail and to the intermediate limiting bar, and the distancebetween the pivotal connections at the ends of the intermediate limitingbars being the same, and the distance between the pivotal connection ofthe upper limiting bars with the front rail and with the intermediatelimiting bar being the same as the distance between the pivotalconnections of the intermediate limiting bar.

3. In a step ladder, front and back rails, a top step pivotallyconnected to the rails, lower limiting bars extending across between afront rail and its adjoining back rail, pivotally connected to the frontand back rails and pivotally connected to one another, stop meanslimiting the motion of the lower limiting bars downward beyond thestraight extension position, upper limiting bars extending acrossbetween the same front and back rails, pivotally connected to the railsabove the pivotal connections of the lower limiting bars and pivotallyconnected to one another and an intermediate limiting bar pivotallyconnected to the lower limiting bars and pivotally connected to theupper limiting bars where they pivotally connect with one another, theupper limiting bars extending in prolongation of one another and thelower limiting bars extending in prolongation of one another when theladder is fully open, the distance between the pivotal connections ofthe upper and lower limiting bars to the front rail being the same asthe distance between the pivotal connection of the lower limiting barsto the front rail and to the intermediate limiting bar and the distancebetween the pivotal connections of the intermediate limiting bar withthe upper and lower limiting bars being the same as the distance betweenthe pivotal connection of the upper limiting bars with the front railand with one another.

4. In a step ladder, front and back rails, a top step pivotallyconnected to the rails, lower limiting bars extending across between afront rail and its adjoining back rail, pivotally connected to the frontand back rails and pivotally connected to one another, stop meanslimiting the motion of the lower limiting bars downward beyond thestraight extension position, upper limiting bars extending acrossbetween the same front and back rails, pivotally connected to the railsabove the pivotal connections of the lower limiting bars and pivotallyconnected to one another, a stop adjacent the pivot of the upperlimiting bars on the back rail, and an intermediate limiting barpivotally connected to the lower limiting bars and pivotally connectedto the upper limiting bars where they pivotally connect with oneanother, the upper limiting bars extending in prolongation of oneanother and the lower limiting bars extending in prolongation of oneanother whe the ladder is fully open, the distance between the pivotalconnections of the upper and lower limiting bars to the front rail beingthe same as the distance between the pivotal connection of the lowerlimitin bars to the front rail and to the intermediate limiting bar andthe distance between the pivotal connection of the intermediate limitingbar with the upper and lower limiting bars being the same as thedistance between the pivotal connection of the upper limiting bars withthe front rail and with one another.

JEROME B. BELL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 421,843 Teal Feb. 18, 18802,136,354 Welsh Nov. ll, 1938 2,160,124 Cast May 30, 1939 2,230,015 RichJan. 28, 1941 FOREIGN PATENTS Number Country Date 26,333 Great Britain1904

